🐛 Fix workspace crash on non-string thumbnail URIs

Thumbnail :uri values arrive from the server over transit, so
media-ids decode to UUID objects instead of strings. The
resolved-uri? helper added in #11563 called
clojure.string/starts-with? on them unconditionally, raising
TypeError: str.lastIndexOf is not a function and crashing the
workspace on frame render. Guard with string? so non-string
URIs fall through to resolve-media, which stringifies them.

AI-assisted-by: muse-spark-1.3-contributor

frontend/src/app/main/refs.cljs

@@ -587,8 +587,9 @@
 (defn- resolved-uri?
   "Returns true if the uri is already a fully resolved URI (blob or data)."
   [uri]
-  (or (str/starts-with? uri "blob:")
+  (and (string? uri)
-      (str/starts-with? uri "data:")))
+       (or (str/starts-with? uri "blob:")
+           (str/starts-with? uri "data:"))))
 
 (defn workspace-thumbnail-by-id
   [object-id]

frontend/test/frontend_tests/main/refs_test.cljs

@@ -0,0 +1,30 @@
+;; This Source Code Form is subject to the terms of the Mozilla Public
+;; License, v. 2.0. If a copy of the MPL was not distributed with this
+;; file, You can obtain one at http://mozilla.org/MPL/2.0/.
+;;
+;; Copyright (c) KALEIDOS SUBSIDIARY SL
+
+(ns frontend-tests.main.refs-test
+  (:require
+   [app.common.uuid :as uuid]
+   [app.main.refs :as refs]
+   [cljs.test :as t :include-macros true]))
+
+(def ^:private resolved-uri? @#'refs/resolved-uri?)
+
+(t/deftest resolved-uri-detects-blob-and-data-uris
+  (t/is (true? (resolved-uri? "blob:http://localhost/thumb")))
+  (t/is (true? (resolved-uri? "data:image/png;base64,iVBOR"))))
+
+(t/deftest resolved-uri-rejects-plain-media-ids
+  (t/is (false? (resolved-uri? "275c9c60-7f5e-4a2b-9f1c-2d3e4f5a6b7c")))
+  (t/is (false? (resolved-uri? ""))))
+
+(t/deftest resolved-uri-tolerates-non-string-uris
+  ;; Thumbnail :uri values arrive from the server over transit, so
+  ;; media-ids decode to UUID objects instead of strings. These must
+  ;; fall through to resolve-media instead of raising a TypeError
+  ;; (str.lastIndexOf is not a function) that crashes the workspace.
+  (t/is (false? (resolved-uri? (uuid/next))))
+  (t/is (false? (resolved-uri? nil)))
+  (t/is (false? (resolved-uri? 42))))

frontend/test/frontend_tests/runner.cljs

@@ -41,6 +41,7 @@
    [frontend-tests.logic.update-position-test]
    [frontend-tests.logic.wasm-modifiers-nil-id-test]
    [frontend-tests.main-errors-test]
+   [frontend-tests.main.refs-test]
    [frontend-tests.plugins.comments-test]
    [frontend-tests.plugins.context-shapes-test]
    [frontend-tests.plugins.file-test]
@@ -138,6 +139,7 @@
    'frontend-tests.logic.groups-test
    'frontend-tests.logic.nudge-selected-shapes-test
    'frontend-tests.logic.pasting-in-containers-test
+   'frontend-tests.main.refs-test
    'frontend-tests.main-errors-test
    'frontend-tests.logic.sidebar-transform-coalescing-test
    'frontend-tests.logic.update-position-test